This invention relates to an apparatus and process for transferring crude oil. More particularly, but not by way of limitation, the invention relates to an apparatus and process to transfer crude oil from a storage location to an oil pipeline.
In the oil and gas industry, when a hydrocarbon reservoir is produced, the well effluent is often a mixture of oil and gas. In order to accurately measure the amount of hydrocarbons produced, as well as to eventually sell the product, the operator finds it necessary to separate the oil and gas. In remote locations, such as offshore or arctic regions, the process for separating the oil and gas is particularly important for economic reasons.
In normal situations, an oil and gas separator is used downstream of the producing well. In this separator, the initial separation of the produced oil, gas, and water takes place. The gas may then be vented out to a gas pipeline, or in the more exotic locations, to a flare where the gas is burned.
The oil thus produced is transferred to a stock tank for further settling and separation of any residual gas. The amount of retention time required depends on the specific physical qualities of the oil and gas.
The oil then must be transferred to a pipeline, or in the case of a drill stem test, the oil is pumped to a flare for burning. In either case, the transfer is completed by a transfer pump which is usually a diesel engine and pump.
Finally, oil is flown through a metering skid which measures the amount of oil produced. The metering device is generally a turbine meter but may also consist of a positive displacement apparatus.
The apparatus and process of the prior art has several distinct disadvantages. First, the use of a diesel pump and engine is expensive. The pumps require a substantial start-up cost and also require regular maintenance and repair. Further, these pumps are very heavy and bulky, and if the use of the pumps is in remote areas, logistical problems require expensive solutions. Finally, the diesel pumps require significant amounts of fuel, which because of the remote location and cost, also exacerbate logistical problems.
Therefore, there is a need for an apparatus and process which can transfer crude oil from a storage location to a pipeline which will eliminate the large and costly use of diesel engines, pumps and metering skids.